Ah yes, but the more resistance the foil sheet is also. Grain boundaries
are
now many. Also, the peel strength adhesion is less. Some suppliers enhance
that surface with silane coupling agents which works very strange with fine
lines.

Groovy

----------
> From: [log in to unmask]
> To: [log in to unmask]
> Subject: Cu Foil Grain size
> Date: Tuesday, July 22, 1997 12:34 AM
> 
> 
> Hi,
> 
> Does anyone know how would the grain size of the matt surface of the Cu
> foil (say 1/2 oz)
> affect the etching performance, peel strength and any other properties of
> the PCB?
> 
> The reason is we have a Cu foil supplied from Japan with very fine grain
> nodules < 1um.
> Then another from Korea with larger grain at the matte surface (1 - 2um)
> under the SEM.
> 
> Smooth side for this Korean foil is also rougher.
> 
> I read one article from the Japan supplier that the smaller the grain the
> faster the etching rate, thus easier and better etching especially for
> fine-lines.
> Any Comment?
> 
> Richard
> 
> 
>
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